The following background information may present examples of specific aspects of the prior art (e.g., without limitation, approaches, facts, or common wisdom) that, while expected to be helpful to further educate the reader as to additional aspects of the prior art, is not to be construed as limiting the present invention, or any embodiments thereof, to anything stated or implied therein or inferred thereupon.
Often, aluminum smelting is the process of extracting aluminum from its oxide alumina, through an electrolytic process, such as the Hall-Héroult process. It is known that the Hall-Héroult process is the major industrial process for the production of elemental aluminum. This process involves dissolving alumina in molten cryolite, and electrolyzing the molten salt bath, typically in a purpose-built cell.
Typically, an oxidizing agent is the element or compound in an oxidation-reduction reaction that accepts an electron from another species. Because the oxidizing agent is gaining electrons, it is said to have been reduced. The oxidizing agent itself is reduced, as it is taking electrons onto itself, but the reactant is oxidized by having its electrons taken away by the oxidizing agent. Common oxidizing agents are known in the art, and include, oxygen, ozone, hydrogen peroxide, sulfuric acid, nitrate compounds, halogen compounds, hypochlorite, and hypohalite compounds. Another possible oxidizer may include nickelferous iron ore.
In many instances, an iron-nickel alloy is a group of alloys that mostly consist of the elements nickel and iron. There is an affinity between nickel (atomic number 28) and iron (atomic number 26). These elements also produce natural occurring alloys, a large number of commercial alloys, and provide a complex electron environment for catalyzing chemical reactions. Chromium is a chemical element which has the symbol Cr and atomic number 24. It is a steely-gray, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point. Chromium metal and ferrochromium alloys are commercially produced from chromite, by silicothermic or aluminothermic reactions, or by roasting and leaching processes.
Iron-nickel alloys may be produced by oxidizing aluminum and/or carbon in the presence of iron oxide or nickel oxide and heat. The process may use iron ore or other suitable compounds as an oxidizing agent. It has been found, however, that using nickelferous iron ore (NIO) as the oxidizing agent results in the production of iron/nickel alloys having higher quality and market value than alloys produced using an oxidizing agent which does not contain nickel or possible chromium.
It is known that environmental remediation deals with the removal of pollution or contaminants from environmental media such as soil, groundwater, sediment, or surface water for the general protection of human health and the environment. Remediation is generally subject to an array of regulatory requirements, and also can be based on assessments of human health and ecological risks where no legislated standards exist or where standards are advisory.
Accordingly, a method of remediating aluminum smelter waste by reacting aluminum dross and/or SPL with nickelferous iron ore (NIO) as an oxidizing agent to produce a nonhazardous, nontoxic slag, and a high-quality iron/nickel alloy by-products is needed.